Which statements correctly explain price floors and price ceilings?

Which statements correctly explain price floors and price ceilings? Check all that apply.

a. Ineffective price floors tend to be too high. Ineffective price ceilings tend to be too low.
b. Price floors help producers by raising prices.
c. Price ceilings help consumers by lowering prices.
d. Effective price floors are set above equilibrium.
e. Effective price ceilings are set below equilibrium.